Tethered Balloon Sounding System. The tethered balloon sounding system consisted of a ground based receiving station and a tethered balloon that could simultaneously have attached up to 6 sondes along the tether line. The system is manufactured by Atmospheric Instrumentation Research, Inc. now a part of Vaisala USA. Each sensor measured temperature, pressure, relative humidity, wind speed and wind direction. Due to technical problems with the sensors, the number of sensors used varied over the period. This did not influence the quality of the high resolution profiles but limited our ability to perform long time series of low resolution profiles by using multiple sensors set at specific heights. The sampling interval depended on the number of sensors attached but the system used approx. 3.5 seconds to sample each sonde when multiple sondes were used, and each sonde were sampled chronologically. With only one sonde attached the sampling interval was 2 seconds. Parameters and units used is listed in the file headers along with the corresponding ground level meteorological values from the ships met-instruments or the SPO/APL tower data. Sonde characteristics. Sensor Range Accuracy Unit Temperature +50 to -40 0.5 deg. C Humidity 0% to 100% 3% Pressure 1050 to 600 1 hPa Wind Speed 0 to 20 0.5 m/s Wind Direction 0 to 360 10 deg. The manufacture provided software had some "bugs" that only allowed calibration of positive temperatures (Celsius). Which prevented us from applying the correct offsets. Correct offsets can be derived using the ground station values included in the file headers. Later versions of the data will be corrected to our best knowledge and also profiles and time series at fixed heights will be extracted from the raw data provided here. More detailed information from the instrument logs will be made available on request. Please send questions regarding this system or the dataset to: Rune Storvold Geophysical Institute, University of Alaska Fairbanks 903 Koyukuk Dr. P.O.Box 757320 Fairbanks, Alaska 99775-7320 USA E-mail: Rune.Storvold@gi.alaska.edu Phone: (907) 474-6639 FAX: (907) 474-7290